1. Field of the Invention
The present invention relates to a pattern mask, a light-emitting unit manufactured by using the pattern mask, a display apparatus manufactured by using the pattern mask, and a method of manufacturing the display apparatus by using the pattern mask. More particularly, the present invention relates to a pattern mask capable of enhancing productivity, a light-emitting unit manufactured by using the pattern mask, a display apparatus manufactured by using the pattern mask, and a method of manufacturing the display apparatus by using the pattern mask.
2. Description of the Related Art
Recently, an information processing apparatus is used in various fields. Data processed by the information processing apparatus generates electric signals. Therefore, the information processing apparatus includes a display apparatus that converts the electric signals into light so that a user may recognize an output processed by the information processing apparatus.
The display apparatus may be classified into an emissive type display apparatus and a non-emissive type display apparatus.
The emissive type display apparatus displays an image using light generated by an emissive element. The emissive type display apparatus include a cathode ray tube (CRT) display apparatus, a plasma display panel (PDP), a light-emitting display (LED) apparatus, etc.
The non-emissive type display apparatus displays an image using light generated by a backlight assembly, an external light etc. The non-emissive type display apparatus include a liquid crystal display (LCD) apparatus, an electrochemical display (ECD) apparatus, an electrophoretic image display (EPID), etc.
The LED may be classified into an organic light-emitting display (OLED) apparatus and an inorganic light-emitting display apparatus depending on materials for emitting light.
Electrons emitted by high voltage collide with light-emitting center of the inorganic light-emitting display apparatus to generate the light.
The OLED includes an anode, a cathode and an organic light-emitting layer interposed between the anode and the cathode. When electrons from the anode are combined with holes from the cathode in the organic light-emitting layer, excitons of high energy are generated. When the excitons are transferred from an excited state to a ground state, light is generated.
In order to form the organic light-emitting layer, a screen-printing method or a printing method may be employed.
According to the screen-printing method, organic light-emitting materials may be formed on proper positions through openings of a mask.
According to the printing method, the organic light-emitting materials may be dropped on predetermined positions. In detail, banks are formed on the anode, and droplets of the organic light-emitting materials are dropped onto cavities defined by the banks. Then, the organic light-emitting materials that fill the cavities are dried to form the organic light-emitting layer.
Recently, as a resolution of the display apparatus is enhanced, the number of anodes per unit area increases, and a distance between the anodes decreases. When droplets of the organic light-emitting material are not dropped onto the positions, yield of the OLED apparatus decreases. In addition, when the droplets of the organic light-emitting material are not dropped onto the cavities, additional droplets are dropped onto the empty cavities so that productivity of the OLED apparatus is lowered.